TiO2@Ag/P (VDF-HFP) composite with enhanced dielectric permittivity and rather low dielectric loss

Abstract

Ag-loaded TiO₂ hybrid particles (TiO₂@Ag) were synthesized as fillers by using an ethylene glycol reduction method. Based on this, the TiO₂@Ag/P(VDF-HFP) hybrid films were prepared by embedding TiO₂ nanoparticles in a poly(vinylidene fluoride-co-hexafluoropropylene) [P(VDF-HFP)] matrix. Morphology and thermal analysis show that the introduction of TiO₂@Ag does not disrupt the continuity of the polymer matrix, while the strong interaction between fillers and matrix influences the crystallization process of the composite. The adhesion of Ag to TiO₂ efficiently separates the Ag particles from connecting and suppresses the formation of a conductive network, and the ultra-small Ag nanoparticles “trap” the carriers due to coulombic blockade and quantum confinement effect, which results in low dielectric loss and electrical conductivity of the composites. As a consequence, the dielectric permittivity of polymer nanocomposites was enhanced by 300% over the P(VDF-HFP) matrix at a filler content of 30 vol% while maintaining a rather low dielectric loss (0.037 at 1 kHz), demonstrating promising applications in electronic devices.